I was walking with my camera strap less like i usually do, that day had really cold weather (around 40 degrees F, which is pretty cold in California. For some reason, my hand froze (i couldn't move it) and my camera dropped out of my hands from about 4 feet up. It fell lens down first. I checked everything really thoroughly. Luckily the camera and lens weren't broken and worked just fine, but the filter was a mess. There was a large dent on the side of the filter as well. I'm not saying that the filter would prevent your gear from cracking or breaking, but this little 10 dollar precaution saved me over 200 dollars. I also learned to always wear the strap, or at least tie it around my hands.

Heres a photo of the Filter, taken with the same camera and lens that was dropped.